1. Field of the Invention
The invention has to do with sheet materials that are taken up on roll cores for storage and shipping. More specifically, the invention is an improvement in rolls of sheet vinyl floor covering and their method of manufacture which prevents damage to the layers of floor covering material that are first wound about the roll core.
2. The Related Art
Roll cores are commonly used to take up carpeting, sheets of vinyl floor covering and other sheet products as a part of the packaging process following manufacture of the carpet or sheet. For many years, manufacturers of roll cores have made a product with a flap attached to the core. The leading edge of the sheet product was placed under the flap to minimize or prevent damage to subsequent layers of the product. This system worked well when the packaging operation was done by hand. But with automation, it became very difficult to line up the flap with the leading edge of the sheet product.
Another solution was to make a thicker roll core and rout an inclined plane along its length. The maximum depth of the plane was sized to correspond with the thickness of the sheet and the leading edge of the sheet was abutted against the edge of maximum depth as the sheet was taken up on the roll. As with the foregoing design, this system worked better when the packaging operation was done by hand. Another drawback was that the maximum depth had to be varied to match the thickness of the sheet. This required a large inventory of rolls in facilities where sheets of varying thicknesses were made.
The present invention overcomes the foregoing problems by providing a solution that works well in automated systems and works well with sheet materials having different thicknesses.